Pyridineacetic acids

Electron-deficient allenes also undergo hetero-Diels-Alder reactions. N,N-Dimethyl-hydrazones 193 reacted with allenedicarboxylate 110a in refluxing acetonitrile to give 2-carboxy-3-pyridineacetic acid diesters [157]. 

Pyridines with an a- or y-carboxymethyl group (e.g. 685) undergo facile decarboxylation by a zwitterion mechanism (685 — 688) somewhat similar to that for the decarboxylation of 3-keto acids (cf. Section 3.2.3.1.1). Carboxymethylpyridines often decarboxylate spontaneously on formation thus, hydrolysis of (689) gives (690). The corresponding 2- and 4-pyridone and 2- and 4-pyrone acids are somewhat more stable, e.g. (691) decarboxylates at 170°C. 3-Pyridineacetic acid shows no pronounced tendency to decarboxylate. 

The homologue of nicotinic acid, 3-pyridineacetic acid (IV) has been evaluated as a hypohpidemic agent in laboratory animals and in man. It was found by several Itahan research groups [54-56] to be comparable or superior to nicotinic acid. qjj COOH... 

C5H5N 110-86-1) see Carbinoxamine Cefaloridine Cetylpyridinium chloride Chlorphenamine Diodone, Pheniramine 4-pyridineacetic acid... 

Chemical Name 1(4H)-Pyridineacetic acid, 3,5-diiodo-4-oxo-, compd. with 2,2 -iminobis(ethanol) (1 1)... 

Pyridineacetic acid 2-Pyrazinecarboxylic acid 8-Hydroxyquinoline HPAA HPyraz HOx... 

Table 8. Data on Np(V) complexation with pyridinecarboxylic and pyridineacetic acids.

Drmanic, S.Z., Jovanovic, B.Z. and Misic-Vukovic, M.M. (2000) A comparative LFER study of the reactivity of pyridineacetic, pyridineacetic acids N-oxide and substituted phenylacetic acids with diazodiphenylmefhane in various alcohols./. Serb. Chem. Soc., 62, 847-856. 

Pyridineacetic and thiazoleacetic acid can also be decarboxylated by way of the zwitterions or analogous cyclic intermediates.20 In these cases the formation of the zwitterion does not lead to electron attraction by the -carbon atom but, instead, produces a cationoid centre at the -position. 2-Ethyl-2-methyl-2-(2 -pyridyl)acetic acid, for instance, is stable in boiling concentrated hydrochloric acid or boiling sodium carbonate solution but is readily decarboxylated in neutral solution. 4-Pyridineacetic acid behaves similarly. Decarboxylation of optically active pyridineacetic acid derivatives having an asymmetric a-carbon atom leads to completely racemic products, and as the racem-ization is simultaneous with, and not subsequent to, the decarboxylation it is assumed that an enamine is formed as intermediate, e.g. ... 

ETHYL 2-PYMDYLACETATE (2-Pyridineacetic acid, ethyl ester)... 

TABLE XI-12. Condensations of Pyridineacetic Acids, Esters, and Amides to give Longer-Chain Acid Derivatives... 

Indenes, from pyridineacetic acid derivatives, 488-490 Indenones, from pyridine hydroxy compounds, 368 Indigoidin, 854 from 3-amino-2,6-pyridinediol, 854... 

Pyridineacetic acids, conversion to pyridine side-chain carboxylic acids, 422-420 dihydro, oxidation with O2,... 

A soln. of N-phenacetyl-2-pyridinesulfonamide 1-oxide in lO -NaOH heated 1.5 hrs. on a steam bath a-phenyl-2-pyridineacetic acid 1-oxide. Y 80.1%. F. e. s. T. Naito, R. Dohmori, and T. Kotake, Ghem. Pharm. Bull. 12, 588 (1964). 

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